Maria de Villota's condition has improved from critical to serious after further surgery at Addenbrooke's hospital.

Friday's successful operation had been planned to address her facial injuries after her accident at Duxford aerodrome on Tuesday. The surgery means her condition is now "serious but stable".

Marussia released the following statement on Friday night: "Earlier today, Maria underwent further surgery at Addenbrooke's Hospital in Cambridge. This was a planned procedure that would depend upon the continued stability of Maria's head injuries, and this morning the medical team were sufficiently happy with her progress to allow the operation to go ahead.

"The surgeons successfully completed the next phase of surgery required to address Maria's facial injuries. After the lengthy initial procedure, which commenced on Tuesday and concluded on Wednesday, today's secondary operation took significantly less time.

"Since the operation today, Maria's condition in relation to the head trauma she received has further improved, to the extent that she is now "serious but stable".

"Whilst Maria remains acutely ill, this confirms that she has been responding well to the treatment she has received since her accident. Coupled with the significant progress that has been made with regard to her facial injuries, we feel sufficiently comfortable to proceed with a further update.

"On a more personal note, we have taken a great deal of encouragement from today's developments and the rather more positive signs for Maria's family."

Several F1 drivers showed their support for de Villota on Friday by running her star logo on their helmets during practice for the British Grand Prix.